PSLE
Mrs Yap had a bottle of wine. She used an equal amount of wine each day. At the end of the sixth day, she had 540 mℓ of wine left. At the end of the eighth day, she had one-third of the bottle of wine left. How many litres of wine were there in the bottle at first?
Fraction of wine used after one-third of the bottle was left
= 1 - ¹₃
= ²₃

²₃ of the bottle → 8 days
1 bottle → 8 ÷ ²₃ = 8 x ³₂ =  12 days

It takes 12 days to finish the whole bottle.

Number of days to use 540 mℓ of wine
= 12 - 6
= 6

6 days → 540 mℓ

1 day → 540 ÷ 6 = 90 mℓ

12 days → 12 x 90 = 1080 mℓ

1000 mℓ = 1 ℓ

1080 mℓ = 1080 ÷ 1000 = 1.08 ℓ

Volume of wine in the bottle at first = 1.08 ℓ

Answer(s): 1.08 ℓ